Yep, general public are not allowed to play with rated utilities.
Even your own soldered/bronzed copper plumbing lines in a new house has to pass inspection. Let alone a gas.
Creating something new with a gas as a coolant would require an engineering certificate, not a technician. Little different for standard products and fitting them, but design anything new and an engineering certificate would be required.
I think this at home without lodging the cert at the insurance office would help void any issues if it all went up and the fire unit found house was guttered by Freon.
Don't get me wrong, love seeing anything posted new and they certainly look the part, thanks for the topic. I'm gathering they were put together by techs though; and would love to see the differences in loads/timing/temps etc and the logs created when testing it all out. Youtube to the rescue. --
The only thing necessary for the triumph of evil is for good men to do nothing - Edmund Burke